Forget complicated meal plans. Build good eating habits around basic food knowledge, and keep these three guidelines in mind.

1. BE REGULAR: The number-one improvement athletes can make to their diets is to structure their eating. Studies have linked regular meals with more consistent blood-sugar levels, lower cholesterol, and increased lean body mass. Recipe for Success: Plan for three meals a day and two snacks in between. Eat every three to four hours to keep hunger at bay.

2. SIMPLIFY: “Eating well doesn’t have to be about restrictions,” says Leslie Bonci, director of sports nutrition at the University of Pittsburgh. “Rather than dwell on every calorie, focus on big-picture needs—proteins, carbohydrates, and fats.” Recipe for Success: Divide every meal into thirds. The first third should be protein, such as fish or chicken; the second, fruits and vegetables; the third, grains.

3. DON'T JUST FILL, FUEL: “A lot of people use exercise as a free pass to eat whatever they want,” says dietitian Kelli Jennings of Apex Nutrition in Golden, Colorado. “Exercise should complement your diet, not sabotage it.” Recipe for Success: Jennings suggests distinguishing between daily eating and ­training nutrition, with an emphasis on performance calories on the days you exercise and healthy, whole-food nutrition on the days you don’t.